Cycloserine-Cefoxitin Fructose Agar – CCFA

Product Description & Summary

Cycloserine Cefoxitin Fructose Agar (CCFA) is an enriched, selective, and differential media used for the isolation and presumptive identification of Clostridium difficile, a recognized cause of pseudomembraneous (antimicrobial agent-associated) colitis.

CCFA is an enriched, selective, and differential media used for the isolation of Clostridium difficile. The basic nutritive base consists of animal peptones and fructose, and is supplemented with cefoxitin and cycloserine at concentrations that inhibit the growth of most normal fecal flora. Cycloserine will inhibit gram-negative bacteria, while cefoxitin will inhibit both gram-positive and gram-negative organisms. Clostridium difficile is not inhibited on CCFA, and when grown, will exhibit a characteristic yellow, ground-glass colonial morphology. Neutral red is added as a pH indicator. The presence of C. difficile will turn the indicator from pink/orange to yellow due to the amino acids being utilized by the organism, increasing the overall pH causing the color change of the indicator. This media is prepared, dispensed, and packaged under oxygen-free conditions to prevent the formation of oxidized products prior to use.

Interpretation of Results & Limitations

If used properly, CCFA supports good growth of C. difficile. After 24-48 hours, most colonies of C. difficile are large, circular, and yellow, with the yellow coloration extending 2–3 mm beyond the colony into the initially pink/orange media. These colonies fluoresce golden yellow/chartreuse under long-wavelength UV light. Most other bacteria are inhibited on this media. At 48 hours, colonies of most other organisms (e.g. Lactobacilli and yeast), which may grow, are very small (pinpoint to 0.5 mm in diameter) and do not fluoresce golden-yellow.

CCFA will not provide complete information for identification of bacterial isolates. Rare strains of C. difficile may be inhibited.  Plates must be examined no later than after 48 hours of incubation for optimal selectivity, as after 3 – 5 days of incubation, significant numbers of colonies other than C. difficile may grow. A test for aerotolerance should be used to confirm that each colony type is an obligate anaerobe. Consult reference materials for additional information.

Quality Control

The following organisms are routinely used for quality control performance testing at Anaerobe Systems.

Product Storage & Shelf Life

Storage: Upon receipt, store at 2 – 8^oC in original package until used. Avoid overheating or freezing. Do not use media if there are signs of deterioration (shrinking, cracking, or discoloration due to oxidation of media) or contamination. The expiration date applies to the product in its original packaging and stored as directed. Do not use product past the expiration date shown on the container.

Shelf Life: 90 days from date of manufacture.